Drill bit



Sept. 25, 1934. w. v. SEIFERT DRILL BIT Filed July 26, 1932 INVENTOR.

ATTORNEY$ Patented Sept. 25, 1934 PATENT; OFFICE ,D BI 'Willi'am- -V. Seifert, Denver, (1010., assignor to Superior Rig and Bit Compa'nm-a corporation of Colorado I Application July' 26,1932, SerialNo. 624,674

' si oiaims. (o1. 255-71) This invention relates to rotary :dri-ll tools of the general type used lincboring wells for oil or water, H v

(It is the principalcobject.ofzthe present invention toprovidea drill .bit whichby its rotary motion willrapidly andefiectively producea smooth bore through earth-formations, irrespective of their densities: ortheir varying degreesof resistance to. the cuttingaction of the tool. It is a=distinctive feature of the invention that by a rotary movement of the tool, :a rapid .hammering and prying action is produced,.resulting in a constant. disintegration and breaking away of the rocker other formation into which the tool is advanced. o Other objects of the invention reside in details of construction and in a novel arrangement and combinationof parts, .all of whichwill fullyappear in the course oi the followingdescription. In the accompanying drawing in the several viewsof which like parts are similarly designated, 1 Figure 1 representsa sectional elevation of the improved tool, i V

Figure 2; a section taken on the line 2-2 of Figurel, i

Figures, asection along the. line 3-3 of Figure. 1, l

Figure 4, a section on the line 4--4, Figure .1,

and

Figure-5r a diagrammatic View showing the manner in which the toolpenetrates the. earth formationby its rotary motion.

Referring further to the drawing, .the numeral 5 designates the tubulardrill stem which, as usual, is mounted for rotationabout its longitudinal axis. In screw-threaded connection with the lower end of-the stem, is a coupling 6for the attachment of a cutter-support' 7 The connection between the coupling member and the support is provided by a tapering screw-threadedistud Boon the .coupling, engaging in a correspondingly threaded socket of the'support. 1 i J The support comprises a block having at its lower-end a -cylindrical arbor 9 at an oblique angle to the longitudinal axis of .the coupling, which is coincident with the axis of. the drill stem. At right angles to the arbor, is a shoulder 10 and at the end of the arbor is a screw-threaded stud 12 of reduced diameter, providing asecond shoulder 13. r v .Mounted wuponthe arbor are three cooperating cutting members, namely, .:a primary cutter 14, a

secondary cutter 15 and a reaming or finishing cutter 16. l H .2.

These cutters have their axescoincidentrwith the. slanting axis of the cutter-support and they are held in their operative relation by means of a fiangedcircularnut 17 screwed upon the stud 12.

; .The primary cutter it bears against the under surface of the arbor 9, herebefore referred to as the shoulder .13, through the medium of a washer 22 of anti-friction material, and it has a central opening in which the nut 17 is fitted. The primary .and secondary cutters are exteriorly conical and they are partially hollowto larlcontour which fits within a correspondingly formed opening of the flange.

Mounted upon the arbor between the second ary cutter and the shoulder of the cutter-support, is the reaming-or finishing cutter 16, whichconsists of a disk exteriorly of conical form, and dished or .concaved at its under surface to provide a sharpcutting-edge 16a. The cutter differs from the others in that it is not toothed but it has in its rim a plurality of openings 160, through which muck and cuttings produced in the operation of the tool may move toward the mouth of the bore.

Between the cutter 16 and the shoulder 10 of thesupport '7 is a washer 18 of anti-friction material. The reamer-cutter 16, as well as the cutters 14 and l5, which.are connected for conjoint movement,.are free to rotate around the arbor 9.

The coupling-member 6 has a bore 19 communicating with the interior of the hollow drill.-

stem and the arbor inclusive of its'stud, and the the bore produced inthe operation of the drill.

Whilethe angle of the axis of the arbor coincident with the axes of the cutting-toolswith relation to .the longitudinal axis of the drill stem,

whichis theaxis of rotation of the tool, may be .varied within an arc of ninety degrees, according to varying conditions, and requirements, it has been found that under normal circumstances an arc of twenty degrees, more or less, is well adapted for the purpose.

In the operation of the tool, the stem is rotated about its axis with the result that the cutters are swung in a gyratory movement. In this movement, the cutters move alternately upwardly and downwardly thereby engaging the rock with a rapid succession of sharp blows which in the nature of a hammering action, disintegrate and dislodge the rockmore effectively and more speedily than could be accomplished by the mere grinding action of the majority of drilling tools, used heretofore in boring wells for water, oil or gas.

The peculiar movement of the cutters of the present drill tool, moreover, produces a prying action of their sharp peripheral edges, upon the rock, it being apparent that in the alternate upward and downward movements of the cutters,

their edges will so to speak, hook under the ledges produced in the rock, resulting inthe prying action above referred to.

As the tool advances by longitudinal movement of the stem, the primary cutter operates as a pilot to initially bite into the earth-formation outwardly from a point substantially in the center of the bore, the secondary cutter being of larger diameter than the primary cutter, enlarges the bore by a similar cutting action, and finally the reaming cutter, which is of larger diameter than the secondary cutter, enlarges the bore to the desired diameter. Since the reaming-cutter is non-toothed, the wall of the bore will be smooth and even.

In Figure 5 of the drawings the lines A--A, BB, etc. of .reverse curvature, indicates the paths of the cutters and in their biting action upon the earth-formations. The outer circle F, shows the path of the reamer or finishing cutter, and designates the circumference of the bore.

In Figure 1, the broken lines G indicate the surface of the bore produced in the operation of the tool. All of the cutters are at all times in contact with the breast of the hole and their cutting edges strike the earth-formations at a high velocity and with a force augmented by the kinetic energy of the cutters.

What I claim and desire to secure by Letters Patent is:

1. A drill tool comprising a support rotatable about its longitudinal axis and a series of circular cutters carried by the support and rotatable about a common axis downwardly inclined to the support axis and meeting same at an obtuse angle, whereby the cutters revolve in orbits about the support axis during rotation of the same, the cutters having cutting edges ranging downwardly at progressively decreasing angles to the common axis of the respective cutters, and the cutters being of decreasing diameters from that nearest the meeting point of the axis downwardly, to progressively engage with the wall of a hole in which the stem is rotated.

2. A well drilling tool including a support having upperand lower ends disposed at an obtuse angle and adapted to rotate on the longitudinal axis of its upper end, the lower end of said support forming a cutter supporting arbor, and a series of inverted cup-shaped cutters nested one within the other and mounted on said arbor.

3. A drill tool including a support having upper and lower ends disposed at an obtuse angle and adapted to rotate on the longitudinal axis of its upper end, the lower end of said support forming a cutter supporting arbor, and a series of inverted cup-shaped cutters nested one within the other and mounted on said arbor, each of said cutters including a disk-like body and a downwardly extending peripheral flange.

4. A drill tool including a support having upper and lower ends disposed at an obtuse angle and adapted to rotate on the longitudinal axis of its upper end, the lower end of said support forming a cutter supporting arbor, and a series of inverted cup-shaped cutters nested one within the other and mounted on said arbor, each of said cutters including a disk-like body and a downwardly extending peripheral flange having a frusto-conical inner surface the axis of which is coincident with the axis of said arbor.

5. A drill tool including a support having upper and lower ends disposed at an obtuse angle and adapted to rotate on the longitudinal axis of its upper end, the lower end of said support forming a cutter supporting arbor, and a series of inverted cupeshaped cutters nested one within the other and mounted on said arbor, each of said cutters including a disk-like body and a downwardly extending peripheral flange having a frusto-conical inner surface the axis of which is coincident with the axis of said arbor, the angles at the apices of the several frusto-conical surfaces being respectively more obtuse in each cutter from the lowermost cutter upwardly.

6. A drill tool including a support having upper and lower ends disposed at an obtuse angle and adapted to rotate on the longitudinal axis of its upper end, the lower end of said support forming a cutter supporting arbor, and a series of inverted cup-shaped cutters nested one within the other and mounted on said arbor, each of said cutters including a disk-like body and a downwardly extending peripheral flange having a frusto-conical inner surface the axis of which is coincident with the axis of said arbor, said flanges having sharp terminal edges and the flanges of the lower cutters being provided with gaps to form teeth.

7. A drill tool including a support having upper and lower ends disposed at an obtuse angle and adapted to rotate on the longitudinal axis of its upper end, the lower end of said support forminga cutter supporting arbor, and a series of inverted cup-shaped cutters nested one within the other and mounted on said arbor, each of said cutters including a disk-like body and a downwardly extending peripheral flange having a frusto-conical inner surface the axis of which is coincident with the axis of said arbor, the angles at the apices of the several frusto-conical surfaces being respectively more obtuse in each cutter from the lowermost cutter upwardly, said flanges having sharp terminal edges and the flanges of the lower cutters being provided with gapsto form teeth.

8. A drill tool including a support having upper and lower ends disposed at an obtuse angle and adapted to rotate on the longitudinal axis .of its upper end, the lower end of said support forming a cutter supporting arbor, and a series of inverted cup-shaped cutters nested one within the other and mounted on said arbor, each of said cutters including a disk-like body and a 9. A drill tool including a Support having upper and lower ends disposed at an obtuse angle and adapted to rotate on the longitudinal axis of its upper end, the lower end of said support forming a cutter supporting arbor, and a series of inverted cup-shaped cutters nested one within the other and mounted on said arbor, each of said cutters including a disk-like body and a downwardly extending peripheral flange having a frusto-conical inner surface the axis of which is 

